BACKGROUND: Studies have shown that young breast cancer patients have more advanced disease and worse survival compared to older patients. Our objective was to study disease characteristics and survival in the subset of young women with hormone receptor positive (HR+) and HER2 negative (HER2-) cancer. METHODS: We retrospectively analyzed HR+/HER2- breast cancer patients who underwent surgery at our institution between 2002 and 2010. We compared clinical characteristics, pathology, treatment, and recurrence-free survival between younger (≤40 years) and older (>40 years) patients. RESULTS: Of 669 HR+/HER2- breast cancer cases, 54 (8.1%) patients were 40 years or younger. Younger patients had more luminal B subtype, high grade, poor differentiation, and increased lymphovascular invasion. Younger women were treated more often with mastectomy and adjuvant chemotherapy. Although the unadjusted recurrence-free survival at median 55-month follow-up was lower in younger women, adjusting for stage, there was no significant difference (90.7% versus 89.3%, p = 0.74) between groups. CONCLUSION: Younger patients with HR+/HER2- breast cancer had more advanced disease and more aggressive treatment than older patients. The unfavorable pathologic features suggest a biologically different tumor in young women. After adjusting for these factors, younger patients have a recurrence-free survival similar to older patients.